Crown sheet support for locomotive fireboxes



Aug. 18, 1931. J. c. MARTIN, JR 1,819,907

CROWN SHEET SUPPORT FOR LOCOMOTIVE FIREBOXES Filed April 2. 1930 4 Sheecs-Shee'l: l

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CROWN SHEET SUPPORT FOR LOCOMOTIVE yFIREBOXES Filed April 2, 1930 4 Sheets-Sheet 2 l O O 4 100Go OQOQOM OO O O O f OO@ O00@ O OOO MU A \\f 000000 v I 0000000 \\4..., 0000000 vl 0000000 Tun.

0 M000 o o O .@OOQQWUJOQO O O @GOGOOOOWH/ J. c. MARTIN, JR l CROWN SHEET SUPPORT FOR LOCOMOTIVE FIREBOXES Aug. 18, 1931.

Filed April 2. 1930 4 Sheets-Sheet 3 ug- 18, 1931 J. c. MARTIN, JR 1,819,907

CROWN SHEET SUPPORT FOR LOGOMOTIVE FIREBOXES Filed April 2. 1930 4 Sheets-Sheet 4 @33% @WTF/.4745

Patented Ang. 18, 1931 UNITED STATES JESSE C. MARTIN, JR., 0F LOS ANGELES, CALIFORNIA CROWN SHEET SUPPORT FOR LOCOMOTIVE FIBEBOXES Application filed April 2, 1930. .Serial No. 440,961.

The hereinafter described invention relates to the generation of steam in locomotive boilers, and more particularly tothe irebox thereof in which water carrying ele. ments are utilized to sustain the crown sheet of the irebox as a measure of safety against serious rupture in the case of a low water covering' thereof and in fact as a safeguard against fatal accidents through crown sheet failures.

One of the objects of myinvention is to provide a hollow strut or column for supporting the crown sheet of a locomotive firebox from the side sheet thereof which will readily adapt itself-to the differential expansion obtaining within the firebox, and my purpose is to construct the column of unlform cross-section from end to end arranged symmetrically about a long and short axis so that'when 4it is set in place in the firebox its fixed ends will possess a minimum radius of gyration for the area of its cross-section,-

thereby providing a construction which will through the iexibilty and hinge-like action of its lfixed or terminal connections effectively compensate the differential movement as set up and consequently preserve the integrity of the column as a support for the crown sheet as well as the integrity of its fixed ends against leakage, cracking and failure.

A further object of my invention is to provide a hollow water-carrying strut for support-ing the crown sheet of a locomotive fireox which will connect the crown sheet to the side sheet of the firebox in a single radius of curvature between -the inlet and outlet thereof and to make the radius of curvature such that it will, in conjunction with the least cross-sectional dimension of the strut, create a hollow curved strut which will serve in effect as a straight column, thereby lending to my Structure a high degree of safety in carrying out the supporting effect intended.

A further object of my invention is to make a hollow curved crown sheet supporting element for the irebox of a locomotive boiler which will be of uniform cross-section throughout its length and whose cross-section will be arranged symmetrically about a long axis and a short axis, the long axis running coincident with the mean radius of curvature of the element and the short axis being substantially at right angles to the longl axis, the element being provided with connecting iange's which. upon attachment form it into a pressure-holding vessel between the crown sheet and the side sheet of the lfirebox.

A further object of my invention is toA tr'c radii, and spaced apart with staybolts,

and to form the plates with integral end flanges, the radii presentin a singleline of curvature between the en flanges, and to bend the curved edges. of the plate into a common joint line and to weld the common joint line of the bent curved edges to seal the element into a pressure-holding vessel.

A further object of my invention is to form a hollow Water carrying strut for attachment to the crown sheet and side sheet of a locomotive firebox of curved' plates so that the strut will have a cross-section arranged symmetrically about a lon and a shortl axis, the platesbeing set apart y staybolts and their curved edges being closed together and welded, the long axis of the strut terminating at thc welded edges of the plates and the short axis being at right angles to the long axis in such manner that the welds are balanced or equi-distant from the intersection of the long and short axes, thereby keeping the welds out of the faces of the curved platesso that when the struts are in place the welds will be along a neutral line to the differential movement of the water residing against the side sheets of the rebox and reducing the strains of exansion and contraction which cause the reakage of staybolts in the side sheets.

A further obJect of my invention is to provide hollow water columns connecting the crown sheet to the side sheets of the firebox which will present their maximum area of surface to the hot gases of combustion within the frebox in planes substantially parallel to the tubular heating surface .of the boiler so that the hot gases will sweep practically the full exterior surface of the columns and equalize the temperature of the metal in the oppositelydisposed plates comprising them, thereby preventing the breakage of staybolts as used 1n holding the plates in spaced relation.

A further object of my invention is to provide a structure which will act to support the crown sheet of a locomotive firebox in a more eflicient manner than has heretofore obtained by dividing the crown sheet longitudinally into a plurality of su porting posts connected to side sheets of t e firebox, which posts will have a long and a short axis symmetrically arranged with respect to the post cross-section and to set the posts so that their longer axes will run substantially parallel with the crown sheet and side sheets lengthwise of the firebox.

. Another object of my invention is to set a plurality' of columns opening into the crown sheet longitudinally therewith ,so that the ascendancy of the steam bubbles generated in the columns will carry water from the side legs of the firebox-to the crown sheet,'as a blanket covering therefor, in keeping it wetted with water in the case of low water in the boiler that would normally expose the crown sheet as a bare surface to the heat of combustion 4of the firebox with destructful results.

In order to fully comprehend my invention reference should be made to the accompanying drawings, in which, Fig. 1 is a longitudinal section of the firebox of a locomotive boiler including its combustion chamber at the forward end thereof, the hollow curved columns of my invention being shown as supporting the crown sheet of the firebox, its full length into the combustion chamber.

Fig. 2 is asectional end elevation of my improvedcrown sheet supporting 'construction taken at two different portions of the rebox, the sectional part at the left of the vertical center line of the firebox being taken on line 2 2, Fig. 1, looking toward the fire door and the sectional part at the right of the vertical center line of the firebox being taken on line 2a-2a, Fig. 1, looking toward the tube sheet end of the firebox combustion chamber.

Fig. 3 is a broken sectional end elevation of a typical firebox with the upper ends of the hollow curved elements of my construcdinal center line thereof as provided by positioning the columns of my improved crown sheet supporting structure with the long axes of their cross-sections running parallel with the crown sheet lengthwise.

Fig.5 is a side elevation of a hollow curved column of my invention showing how it is constructed with a single mean radius of curvature between its flanged terminals, the weld line at one end of its long axis of the column cross-section being shown.

Fi 6 is an end view of the bottom connecting ange of the column of Fig. 5 showing the water passage through the column as formed symmetrically about the long and short axis of the column section, the staybolts separating the two plates of which the column is formed being' shown.

Fig. 7 is an end view'of the top connecting flange of the column of Fig. 5.

Fig. 8 is aside elevation of, my improved curved hollow column and Fig. 9 is a section taken on line 8 8, Fig. 8, showing the uniform cross-section of the column between its fianged ends.

Fig. 10 is a perspective view of the hollow curved column of m invention to illustrate further itsdetail o its construction.

Referring to the drawings,I numeral 10 designates the hollow curved columns of my improved crown sheet supporting structure which are used on either side of the firebox in the typical illustration of the invention as shown. The columns 10 are connected to the crown sheet 11 of the firebox by their top as denoted by the word weld on the drawv 1n s. v

il desire it to be understood that I do not make any claim to the manner of attachment of the flanges of my elements or columns to the respective sheets of the firebox, as the practice which I employ is old and well estabige-i een? lished being that,as instructed bythe Department of Commerce,.Steamboat lnspection Service, Board of Supervising Inspectors, as early as 1915 in their published rules and regulations and which rules and regulations are now theaccepted practice of the Bureau of Locomotive Inspection, Interstate Commerce Commission, under whom resides the jurisdiction of all locomotive boilers in the interests of safety. These rules and regulations provide that where sections ot the sheets of the Firebox are removed and replacement thereof is made by a new piece ot plate that staybolts shall pass through the body of the new plate as be'ore,-the welded edges to be Vd or beveled along the joint prior to welding. rlhe flanges of the columns l0 oit my construction being made ot new plate of a like character as the plates of the firebox are therefore joined to the crown sheet 11, and the side sheets 13, in like manner as specied in the aforesaid rules and the crown staybolts 15 pass through the body of the top flange 12 in substantially the same spacing as before. 'lhe staybolts 15 are screwed into the wrapper sheet 16 or outside shell ot the iirebox like the adjacent crown sheet bolts are secured thereto. lhe bottom flange 14 is provided with staybolts 17 passing through it into the irebox wrapper sheet 16, in the same manner and with substantially the same spacing as that originally existing in staying the irebox side sheets 13 to the wrapper sheet 16. The edges ot the top and bottom connecting flanges 12 and 191, respectively, are beveled tofo and welded to the edges of the openings cut in the crown sheet 1l, and side sheets 13, to receive them. 'llhe welds of the the cut out portions of the crown sheet and side sheets all reside between rows of staybolts as shown. rlhis approved practice assures that the terminal connections ot my improved hollow curved crown sheet supporting columns 10, will be safely and reliably made at all timesn 1n their manner ot attachment my hollow supporting columns 10 may be said to provide tubular patches between the respective openings cut in the crown sheet 11 and side sheets 13 to receive them, the flanged ends ofthe columns as welded and staybolted in place acting as closures tor the openings made in the respective rebox sheets in conformity with Federal rules and regulations.

Now that 1 have covered the manner in which l connect my columns to the rebox sheets, l will proceed with the construct1on of my improved crown sheet column support as set in place in order that its new and novel features and advantages may be disclosed. As illustrated in the. drawings, my columns 10 are made of like plates as the sheets of the ir'ebox, two plates 18 and 19 being used in each column and set apart byI staybolts 20,

and both 'plates being curved with concentric radii 4so that they provide a substantially parallel passa e for water throughout their length, 3%"- wi e and 1211/4- long, which dimensions 1 have found suit the purposes of my structure well. l

l place the curved plates 18, of lesser radii so that they face inwardly toward the side sheets 18 and crown l`sheet 11, and the curved plates 19 so that they, tace loutwardly into the center ot lthe lirebor. The two curved plates 18 and 19 are bent down along their edges into a common joint line 21, and theirl ends are turned over to form the top and bottom connecting anges 12 and 11,' respectively, the abutting edges of the plates being welded so as to form the columns 10 into pressure tight vessels for the passage ot water therethrough upon attachment to the crown sheet 11 and side. sheets 13 of the rebon.

F rom the 'foregoing and by reference to the cross-section of column 10,. F ig. 1, it will be clear that my hollow curved columns are made with a uniform cross-section arranged symmetrically about a long axis 22 and a s ort axis 23, and that the curved plates 18 and 19 forming the sides of the columns run parallel to the long airis 22 and substantially parallel to the side sheets 13, and the crown sheet 11, while the short axis 23, presents the width of the column as its least lateral dimension to the crown sheet 11 and side sheets 13.

1 have discovered that in attaching my columns 10 of long and short anis and ot uniform curvature between ltheir connecting flanges and in the aforesaid manner that l can secure a new and novel supporting construction which gives to the column 1() the elect of straight columns in their ability to support the crown sheet 11.

ln constructing my columns 10 ll make the radius of single curvature between their top and bottom flanged ends 12 and 1t, respectively, more than 8 times the least cross-sectional dimension of the column which measures 1 over-all width across its two curved sheets 18 and 19, ln fact l have elected to make he mean radius of curvature of the two plates 18 and 19, 36 or nine times the least cross-sectional dimension of my columns, in order that l may be well within the rules overning straight columns as set out for re erence by Morleys Strength of mate- ,v

rials quoted in Marks Mechanical Engineers Handbook, (page L1110) which states that Simple beam equations apply when the -radius of curvature of a curved beam is large (8 to 10 times) compared to dimensions of its isav attached and prevent failure by cracking closely adjacent the top and bottom connecting flanges12 and 14, respectively. The differential movement of the iirebox sheets to which my columns 10- are attached is occasioned by the varying conditions of temperature obtaining in the firebox under the intermittent heavy and light firing in road service of the locomotive, causing rapid changes of expansion and contraction in the irebox sheets. By placing the short axis 23 of my columns 10 as the least lateral dimension to the side sheets and crown sheet 13 and 11, respectively, as I do, I reduce the radius of gyration at the column connections causing a hinge-like effect at its terminals, which reserves the integrity of the column for o'ng 'and continuous duty in the exacting service where it is used. The value of this new and novel feature and' advantage of my invention can be well brought out by comparison of the columns 10 of my construction as set in place in the irebox with a circular column connected in like manner to the crown sheet and side sheets 11 and 13, respectively, and in which the arca for Water passage through the two columns is the same. I will use as an example the column 10 of my construction as herewith presented, which has a short axis 23, of internal width 3.25, and a long' axis 22, of

- internal length 13.25, as compared to a circular column 6.29 in diameter, both columns having the same net area for the passage of water therethrough, or 31.05 sq. in. af er deducting for the three staybolts 2O as used in its construction. I

It will be clear that the circular column in presenting its least lateral dimension to the side sheets 13 and the crown -sheet 11 will present its diamter or 6.29 as against the least lateral dimension of 3.25 in the column of my construction and insomuch as the radius of gyration of both columns as set in place in accordance with my invention is dependent upon the least lateral dimension thereof, it follows that I have produced. through my structure a supporting column 1() which will havepractically one-half the radius of gyration of a circular column of like area for water passage, and consequently will provide a materially superior hingelike effect or iiexibility at. its lian'ged top and bottom connections 12 and 14, respectively, over the equivalent circular column.

. I desire to set out the manner in which I form the two plate welded column of my c'onstruction so that it will withstand the arduous duty ot service exacted of it. The column cross-section is made with a long and a short axis denoted as by the numerals 22 and 23, respectively, in the drawings. Two plates of the same thickness and quality as used in the sheets of frebox are curved on concentric radii to a single mean radius of curvature and separated by staybolts 20. The ends kof the curved plates are turned over to form the top and bottom connecting flanges 12 and 14, respectively, and the edges of the curved plates are bent or closed vtogether along a common joint line 21, which line resides at either end of the long axis 22 of the column cross-section. The common joint lines 21 and the edges of the turned over ends of the curved plates, as used to form the top and bottom connecting flanges 12 and 14, respectively, are welded together to seal the column into a pressure holding vessel. By this construction I keep the welds out of the flat curved surfaces of the Icolumn and avoid the use of staybolts running parallel to thelong axis of the column cross-section as would be required to hold the plates together if thus welded in addition to the staybolts 2O parallel to the short axis 23 in order to' accord with Federal requirements in locomotive practice which do not allow credit 4for the strength of the-weld.

In my new and novel construction of column 10, in protection of the welded joints 21 thereof, I use only staybolts running parallel to the short axis 23 of the column crosssection and provide that the welded joints 21 will reside along a line as formed by closing the curved edges of the plates 18 and 19 together, which will be at the ends ofthe long axis 22 of the column cross-section and as sujch, will be neutral to the differential movement of the two spaced plates when subjected t0 the temperature changes in the lirebox, and so that the welds will carry the least strain possible as an insurance against cracking and excessive cost of maintenance in service. The welds of the column 10 of my structure, as aforesaid described, may be said to be balanced on either side of the common center of the long and short axes 22 and 23 of the col-y umn cross-section.

The column is of substantially uniform cross-section throughout its length with the exception o its openings immediately at the ends which Hare out by reason of turning over the ends of the curved plates 18 and 19 to form the top and bottom flanged ends l2 and 14, respectively.

I desire it to be understood that the s acing of the staybolts 20 and the welding o the edges of the plates 18 and 19 are in full conformity with the Federal requirements of the Bureau ofl Locomotive Inspection, Interstate Commerce Commission, assuring the safety of my column structure as a pressure holding vessel upon attachment to the side sheets and crown sheet of the firebox, 13 and 1'1, respectively.

The illustrative embodiments of my invention as herewith set out show the preferred form of cross-section of my hollow curved column in which the section is symmetrical about its axes, the long axis being 31A? times the length of the short axis, al-

though I may, without departing from the principles of the invention, employ other elongated shapes of .column cross-sectionv symmetrically arranged about its axes within the limit of slenderness as a supporting member in which the axes are substantially at right angles to each other and the columns when set between their fixed ends will present their least lateral dimension to the crown sheet 11 and side sheets 13 of the firebox to which they are attached.

I may also resort at some future time to the use of a hollow drawn tube in the construction of my improved crown sheet supporting column or strut, which tube may be processe hot or cold and be squashed, so to speak, to form a column of uniform cross-section arranged symmetrically about a long and short axis, the column to be set with its long axis substantially parallel to the crown sheet and side sheet surfaces and its short axis at right angles to these surfaces in the manner as heretofore set out in carrying out the principles of my invention.

l desire to point out that in making my column with a single mean radius of curvature between its ends, the mandrel upon which it is formed can be withdrawn from either open end thereof; whereas, if a compound curve were employed the mandrel could not be withdrawn from the open ends of the element and the cost of'its manufacture would be materially increased.

rlhis feature of construction in the formation of the column, made possible by its uniform curvature from end to end, is new andnovel.

l now wish 'to refer to the illustrations of my invention as covered by Figs. 3 and t, so that l may bring out the new and novel function of my hollow curved columns l0, as oc casioned by their placement between the side sheets 13 and the crown sheet ll in providingI a wetted covering for the crown sheet in the case of low water in the boiler.

'llhe illustration of Fig. 4 is a diagraminatical plan view of the crown sheet 1l showing the outlets 24 therethrough as provided upon connecting the top flanges l2'of my curved hollow columns 10 to the crown sheet 1l. The outlets 24: form a plurality of elongated openings running longitudinally of the crown sheet on either side of its center line in such manner that the water ascending through the columns lO will be discharged over the top of the crown sheet 11 as a blanket covering therefor.

The movement of water within the columns 10 as created by the generation of steam bubbles therein from the heat of combustion in the ireboX is upward from the water legs t-o the crown sheet as shown in'Fig. 3, the discharge of saturated steam and water through the longitudinally running outlets 24, of the ,"5 columns carrying over the full area of the top of the crown sheet 11 and keeping it well wetted even though the water of the boiler as shown by the water column gauge glass may have gone .down as indicated by line A-B, Fig. 3, below the line of safety as set for protection of the crownl sheet. Such lfunction of my crown sheet supporting structure through the plurality of discharge outlets 24, of its hollow columns 10, as arranged, is a safeguard against low water and the fatal accidents resulting from the failure of the crown sheet.

The embodiment of my invention as set out in the drawings, Figs. l and 2, shows the structure as applied to the irebox of a coal burning locomotive in which the usual brick arch supported on arch tubes resides over the fuel bed in the established manner of practice, however, mfy "invention is equally applicable to a fire box burning fuel oil and the arch tubes and brick arch may or may not be used, at the discretion of those installing my structure, as they do not form any part of my invention..

l desire it to be understood that in my invention as herewith illustrated, described and claimed the sheets of the combustion chamber of the iirebox to which the bottom connecting anges le of my columns l0 are attached are considered as the side sheets of the firebox and that the lower half of the water space surrounding the combustion chamber with which vthe bottom ends of columns 10 communicate are considered as the legs of the ireboxi. y

Minor changes may be made in the physical embodiment of the invention within 'the scope of the appended claims without departing from the spirit thereof.

ll claim:

- l. ln a crown sheet supporting structure for a locomotive firebox, a hollow water carrying column having a cross-section arranged symmetrically about a long and a short anis set at right angles to each other, connecting ends on said column secured to the side sheet and crown sheet of the firebox and communieating with the water leg of the rebox and the water space over the crown sheet, said column having a single radius of curvature between its connecting ends concave toward the connected sheets, and cross-sections adjacent its connecting ends with long axes substantially parallel to the horizontal longitudinally extending center line of the firebox.

2. In a crown sheet supporting structure for a locomotive firebox, a hollow water carrying column having a cross-section arranged symmetrically about a long and a short axis set at right angles to each other,.connecting ends on said column secured to the side sheet and crown sheet of the firebox and communieating with the water leg of the firebox and the water space over the crown sheet, said 'column having parallel curved walls of a mit dit@

lll@

4axis set at right angles to each other, connecting ends on said column secured to the side sheet and crown sheetof the irebox and communicating with the water leg of the firebox and the water space over the crown sheet, said column having a single radius of curvature between its connecting ends more than eight times the length of the short axis of the column cross-section concave toward the connected sheets, and having column crosssections adjacent the connecting ends of said column with long axes substantially parallel to the horizontal longitudinally extending center line of the 'firebox 4. In a crown sheetsupporting structure for a locomotive yirebox, a plurality of hollow curved water carrying columns, each of said columns having a cross-section arranged symmetrically about a long and a short axis set at right angles to each other, connecting ends on said columns joined to the side sheets and crown sheet of the rebox and communieating wtih the water legs of the irebox and the water space over the crown sheet, said columns having a single radius of curvature between their connecting ends concave toward the connected sheets and cross-sections adjacent their connecting ends having their long axes substantially parallel to the horizontal longitudinally extending center line of the firebox, the juncture of said columns with the crown sheet dividing the crown sheet into a plurality of elongated openings residing on either side of the longitudinal center line thereof.

5. In a crown sheet supporting structure for a locomotive fire box, in combination, an inner side sheet and a crown sheet, a hollow water .carrying and crown sheet supporting column having its lower end secured to and opening through the side sheet adjacent its lower portion andits upper end secured t0 and opening through the crown sheet at a point spaced from the side sheet, the axis of said column continuously curved between its ends upon a single radius of curvature concave toward the connected sheets.

6. In a crown.sheet supporting structure for a locomotive iire box, in combination, an inner side sheet and a crown sheet, a hollow water carrying and crown sheet supporting column having its lower end secured to and opening through the side sheet adjacent its lower portion and its upper end secured to and opening through the crown sheet at a point spaced from the side sheet, the axis of said column continuously curved between its ends upon a single radius ofcurvature'concave toward the connected sheets, andsaid radius being sufficiently long to cause said column to function in the same manner as a straight supporting column.

7. A water carrying column for connection to the side sheet and crown sheet'of a locomotive irebox comprising hollow metal walls staybolted together and symmetrically formed from end to end about a long and a short axis set at right angles to each other, said column having'its walls vas residing on either side of the long axis thereof bent to a single radius of curvature and its ends turned over to form connecting flanges, said flanges.

presenting edges adapted to be welded to the respective lirebox sheets.

8. A water carrying column for connection to the side sheet and crown sheet of a locomotive fire box comprising hollow metal walls staybolted together and symmetrically formed from end to end about a long and a short axis set at right angles to each other, said column having its walls as residing on either side of the long axis thereof bent to a single radius of curvature more than eight times the length of the short axis thereof and its A ends turned over to form connecting iian ges, said flanges presenting edges adapted to be Welded to the respective irebox sheets.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 29th day of March, 1930.

JESSE C. MARTIN, JR. 

